Obama camp goes on the offensive, preempts McCain's Houston event with a media call, statement attacking his rival on energy proposals.
Sen. Nelson on call: "It doesn't take a rocket scientist to figure out you can't drill yourself out of the problem -- you have to turn to alternative fuels."
Obama statement:"...his decision to completely change his position and tell a group of Houston oil executives exactly what they wanted to hear today was the same Washington politics that has prevented us from achieving energy independence for decades."
